Mixed with the dirt particles in the hydraulic oil, hydraulic systems and components in the fabrication, Assembly, storage and transportation will be dirt mixed system; using the leak or leaks in the formation of insoluble; use metal parts of wear debris; mixed with dust in the air, and so on, these are easy to form a hydraulic oil particles in the dirt. Hydraulic oil mixed with particles in the dirt, prone to abrasion, reduced hydraulic oil lubrication and cooling performance. There are several causes of contamination by solid particles:

1, hydraulic system itself, the original residual impurities, such as manufacturing of Assembly process, has not been completely clear;

2, the new oil contains impurities because of oil flowing through the pipeline and storage of oil barrels containing impurities;

3, the wild outdoor work environment, all kinds of dust particles into the hydraulic system;

4 maintenance disassembly and Assembly, hydraulic system components and pipes and other pollutants in the process of invasion, or oil, dirty oil change used filter pollutants into the container;

5, from mechanical friction, deformation and the chemical reactions, such as pollution.